German patent DE 103 25 920 B4 discloses a setting tool for fastening elements, which tool can be driven by means of expandable gases, comprising a piston guide in which a driving piston can be movably supported and a piston return device by means of which the driving piston can be moved into a starting position again after a setting operation, wherein the piston return device has a drive means powered by an electric motor and at least one transmission device for transmitting the motor-powered positioning force to the driving piston.